Anti-erosion and anti-falling drilling fluid filtering structure for petroleum drill rod and fluid filter

Abstract

The invention discloses an anti-erosion and anti-falling drilling fluid filtering structure for a petroleum drill rod and a fluid filter. The liquid filtering structure comprises a flow guide base, an internal flow filtering pipe and an anti-skid handle which are in threaded connection in sequence and are coaxially arranged; the internal flow filter pipe and the anti-skid handle are both arranged in the flow guide cavity of the second drill rod, the internal flow filter pipe comprises a conical pipe body, and a first filter hole array and a second filter hole array are alternately distributed in the pipe wall circumferential direction of the conical pipe body. The jet flow momentum is counteracted through filtration from outside to inside and axial drainage of the flow guide sealing part and superposition of the double-filtration-hole array which is symmetrically distributed on the circumference, and erosion damage is fundamentally eliminated; visual omission prevention is realized by the exposed anti-slip handle, and human accidents are completely eradicated; the aperture and wall thickness parameters of the filter holes are adjustable, and a three-section threaded connection structure is matched, so that modular maintenance is realized, and the use cost is reduced; the three circles of concentric circle overflowing holes, the double-chamfer design and the stainless steel material manufacturing ensure high flux, long service life and high reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wellhead tools for oil drilling engineering, and particularly relates to an anti-erosion and anti-falling drilling fluid filtering structure for an oil drilling rod and a liquid filter. BACKGROUND

[0002] In oil and gas well drilling construction, the oil drilling rod bears the dual functions of transmitting torque and conveying drilling fluid, and is a key channel of the drilling fluid circulation system. With the wide application of directional drilling technology (aiming at developing complex oil and gas reservoirs, improving recovery efficiency and solving ground limitations), the use of downhole tools such as screw drill tools, turbine drill tools and rotary steering tools is increasingly common. In order to ensure the normal operation of the trajectory monitoring instrument such as MWD and downhole power drill, a drilling fluid filter must be used to filter impurities and solid particles to ensure the smooth implementation of directional construction. However, the existing drilling fluid filter has the following two fundamental defects:

[0003] Firstly, the traditional filter is funnel-shaped (large at the upper end and small at the lower end), and its filtering mechanism is that the drilling fluid first enters the inside of the filter, and then flows outwards through the wall filter hole. This structure causes the filtered drilling fluid to form a high-speed oblique jet, which directly impacts the inner wall of the drilling rod, causing the anticorrosion coating to fall off, the falling-off coating fragments to contaminate the drilling fluid in the opposite direction and to block the precision instruments at the bottom of the well, and in severe erosion, even forming erosion pits in the inner wall of the drilling rod and piercing the pipe wall, causing the drilling rod to break and fail and causing engineering accidents.

[0004] Secondly, the traditional filter is installed in the internal thread joint of the wellhead drilling rod, and the operation process requires that it must be taken out and transferred to the next drilling rod in the mouse hole before the single rod is connected. However, due to the hidden structure and the difficulty in observation, the wellhead operator is easy to forget to take it out after the single rod drilling or the downhole grouting, causing the filter to be lowered into the bottom of the well together with the drill tool, resulting in additional construction cost and human engineering accidents.

[0005] Therefore, due to the design defects of the filtering direction and the lack of visibility, the existing technology cannot simultaneously solve the two safety hazards of erosion damage and operation omission, and a new type of filter with visible structure, anti-erosion and changeable filtering direction is urgently needed to fundamentally eliminate the above risks. SUMMARY

[0006] The present application provides an anti-erosion and anti-falling drilling fluid filtering structure for an oil drilling rod and a liquid filter, to solve the technical problems of the erosion damage of the inner wall of the drilling rod, the falling-off of the anticorrosion coating and the easy omission into the well during the single rod connection operation due to the high-speed jet impact of the drilling fluid of the traditional drilling fluid filter in the prior art.

[0007] In view of the above technical problems, the present application provides an anti-erosion and anti-falling drilling fluid filtering structure for a petroleum drill rod, comprising a flow guide base, an inner flow filtering pipe and an anti-skid handle which are sequentially and coaxially connected; the flow guide base is connected with a mounting clamping groove seat of a first drill rod, and a connecting coupling head of the first drill rod is threadedly connected with a flow guide cone part of a second drill rod;

[0008] The inner flow filtering pipe and the anti-skid handle are arranged in a flow guide cavity of the second drill rod, the inner flow filtering pipe comprises a conical pipe body, a connecting stud arranged on the conical pipe body and threadedly connected with the anti-skid handle, and a butt joint screw seat arranged on the conical pipe body and threadedly connected with the flow guide base; a first filter hole array and a second filter hole array are arranged in the circumferential direction of the pipe wall of the conical pipe body; the first filter hole array is composed of multiple layers of first filter hole units arranged in the circumferential direction of the pipe wall of the conical pipe body, and each layer of the first filter hole unit comprises multiple uniformly distributed circular filter holes;

[0009] The second filter hole array is composed of multiple layers of second filter hole units arranged in the circumferential direction of the pipe wall of the conical pipe body, and each layer of the second filter hole unit comprises multiple uniformly distributed strip-shaped filter holes.

[0010] Optionally, the first filter hole array is composed of 40 layers of the first filter hole units, and each layer of the first filter hole unit comprises 12 uniformly distributed circular filter holes;

[0011] The second filter hole array is composed of 4 layers of the second filter hole units, and each layer of the second filter hole unit comprises 6 uniformly distributed strip-shaped filter holes.

[0012] Optionally, the diameter of the circular filter hole is 6 mm, and the center distance between adjacent circular filter holes in each layer of the first filter hole unit is 12 mm;

[0013] The length of the strip-shaped filter hole is 20 mm, and the width is 6 mm; the center distance between adjacent strip-shaped filter holes in each layer of the second filter hole unit is 25 mm.

[0014] Optionally, the flow guide base comprises a hanging clamping part, a flow guide sealing part and a first chamfer connected between the hanging clamping part and the flow guide sealing part; the hanging clamping part is threadedly connected with the butt joint screw seat, the flow guide sealing part is clearance-fitted with the mounting clamping groove seat of the first drill rod; a plurality of overflow holes for the flow of drilling fluid out of the conical pipe body are arranged on the flow guide sealing part.

[0015] Optionally, 19 flow holes with a diameter of 10 mm are arranged on the flow guide sealing part, and the flow holes are arranged in a three-circle concentric circular array, and the number of the flow holes in each circle from inside to outside is 1, 6 and 12, and the radial spacing between adjacent circles is 4 mm.

[0016] Optionally, the anti-skid handle comprises a holding part and anti-skid steps connected at both ends of the holding part, and a threaded connection part is arranged on the anti-skid step close to the inner flow filter pipe, and the threaded connection part is threadedly connected with the connecting stud.

[0017] Optionally, a second chamfer is arranged between the anti-skid step and the holding part.

[0018] The application also provides a liquid filter comprising the anti-erosion and anti-falling drilling fluid filtering structure for a petroleum drill rod.

[0019] The beneficial effects of the application are reflected in four aspects:

[0020] Firstly, the erosion damage is fundamentally eliminated, the axial drainage design of the flow holes in the flow guide sealing part bottom by the outer to the inner filtering and the symmetrical arrangement of the multi-layer circular filter holes and the multi-layer strip-shaped filter holes in the circumferential direction of the conical pipe body are superimposed, so that the circumferential direction of the flow channel is completely balanced, when the drilling fluid enters the inside of the inner flow filter pipe 2 (conical pipe body 21) from all directions, the high-speed jet momentum is offset, the local erosion of the inner wall of the filter pipe is avoided, the structure of the filter is reversely protected, the service life is prolonged, and the risks of coating falling, wall piercing and drill pipe breaking caused by the outward jet of the traditional filter are eliminated. Secondly, the operation omission is completely eliminated, the anti-skid handle is exposed to the connecting coupling head of the first drill rod, and the wellhead personnel must actively take out the filter after the operation of connecting the single rod, so as to fundamentally solve the human accidents caused by the observation of the traditional concealed structure and the forgetting to take out. Thirdly, the parameterization adaptation and modularization maintenance, the filter hole diameter and wall thickness can be flexibly adjusted according to the cleanliness and sand content of the drilling fluid, the differential array design of the dense arrangement of the circular filter holes for main filtering and the sparse arrangement of the strip-shaped filter holes for anti-clogging ensures the flow area and meets the large displacement construction requirement, the three-section threaded connection structure (flow guide base, inner flow filter pipe and anti-skid handle) allows the damaged parts to be replaced separately, and the maintenance cost is significantly reduced. Fourthly, the comprehensive performance is improved, the three-circle concentric circular array of 19 flow holes (1-6-12 hole number increasing) ensures the uniform and smooth outflow, the first chamfer between the suspension clamping part and the flow guide sealing part and the second chamfer between the anti-skid step and the holding part eliminate the stress concentration and the risk of operation scratch, and the whole adopts 304 stainless steel material, so that the filter has the comprehensive advantages of high flux, long service life and high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0022] Figure 1 is the overall structure schematic diagram of the anti-erosion and anti-falling drilling fluid filtering structure for the oil drilling rod in an embodiment of the present application;

[0023] Figure 2 is the installation structure schematic diagram of the anti-erosion and anti-falling drilling fluid filtering structure for the oil drilling rod in an embodiment of the present application;

[0024] Figure 3 is the front view of the inner flow filtering pipe in an embodiment of the present application;

[0025] Figure 4 is the sectional view of the inner flow filtering pipe in an embodiment of the present application;

[0026] Figure 5 is the sectional view of the flow guide base in an embodiment of the present application;

[0027] Figure 6 is the top view of the flow guide base in an embodiment of the present application;

[0028] Figure 7 is the overall structure schematic diagram of the anti-slip handle in an embodiment of the present application.

[0029] The reference signs in the description are as follows:

[0030] 1-flow guide base, 11-hanging clamping part, 12-first chamfer, 13-flow guide sealing part, 14-flow hole, 2-inner flow filtering pipe, 21-cone-shaped pipe body, 22-connection stud, 23-butting seat, 24-circular filtering hole, 25-strip-shaped filtering hole, 3-anti-slip handle, 31-holding part, 32-anti-slip step, 321-threaded connection part, 33-second chamfer, 4-first drilling rod, 41-installation clamping groove seat, 42-connection coupling head, 5-second drilling rod, 51-flow guide cone part, 52-flow guide cavity. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clearly understood, the following will further describe the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0032] In the description of the present application, it is to be understood by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0033] In the description of the present application, it is to be understood that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] As Figures 1 to 7 An embodiment of the present application provides an anti-erosion and anti-falling drilling fluid filtering structure for oil drill pipe, which comprises a flow guide base 1, an inner flow filter pipe 2 and an anti-skid handle 3 which are connected in sequence and coaxially arranged; the flow guide base 1 is clamped with a mounting clamping groove seat 41 of a first drill pipe 4, and a connecting coupling head 42 of the first drill pipe 4 is threadedly connected with a flow guide cone part 51 of a second drill pipe 5.

[0035] The inner flow filter pipe 2 and the anti-skid handle 3 are arranged in a flow guide cavity 52 of the second drill pipe 5, the inner flow filter pipe 2 comprises a conical pipe body 21, a connecting stud 22 arranged on the conical pipe body 21 and threadedly connected with the anti-skid handle 3, and a butt joint screw seat 23 arranged on the conical pipe body 21 and threadedly connected with the flow guide base 1; a first filter hole array and a second filter hole array are distributed in the circumferential direction of the wall of the conical pipe body 21; wherein the first filter hole array is composed of multiple layers of first filter hole units distributed in the circumferential direction of the wall of the conical pipe body 21, and each layer of the first filter hole unit comprises multiple uniformly distributed circular filter holes 24.

[0036] The second filter hole array is composed of multiple layers of second filter hole units distributed in the circumferential direction of the wall of the conical pipe body 21, and each layer of the second filter hole unit comprises multiple uniformly distributed strip-shaped filter holes 25.

[0037] The flow guide base 1 can keep the inner flow filter pipe 2 centered inside the second drill pipe 5, and the uniform gap ensures good filtering effect. The flow guide base 1 can also prevent the inner flow filter pipe 2 installed on the upper part from falling into the well due to damage. The first drill pipe 4 and the second drill pipe 5 form a drill pipe unit, and multiple drill pipe units are connected in actual use. The inner flow filter pipe 2 has the functions of filtering drilling fluid and reducing the impact of the drilling fluid jet on the inner wall of the drill pipe. The shape of the inner flow filter pipe 2 is a conical pipe with a small upper end diameter and a large lower end diameter. The outer diameter of the lower end of the inner flow filter pipe 2 is consistent with the inner diameter of the upper end of the flow guide base 1. The size of the circular filter holes 24 and the strip-shaped filter holes 25 can be determined according to the cleaning requirements of the drilling fluid, such as 4 mm, 6 mm, 8 mm, etc. The wall thickness of the inner flow filter pipe 2 can be determined according to the sand content of the drilling fluid, such as 3 mm, 4 mm, 5 mm, etc. The anti-slip handle 3 is connected to the inner flow filter pipe 2 and is used to take out the connected fluid filter structure and put it into the next drill pipe in the mouse hole.

[0038] In the present application, through the three-section threaded connection structure of the flow guide base, the conical inner flow filter pipe and the anti-slip handle, the anti-erosion mechanism of the drilling fluid filtering from outside to inside is realized. The flow guide base not only positions the inner flow filter pipe centrally in the second drill pipe and ensures uniform filtering gap (between the inner flow filter pipe and the inner wall of the drill pipe), but also designs the flow holes of the flow guide sealing part to force the filtered liquid to flow in the axial direction parallel to the inner wall of the drill pipe, completely eliminating the risk of coating shedding and wall piercing caused by the outward jet of the traditional filter. At the same time, the exposed anti-slip handle makes the fluid filter structure have high visibility and convenient operability during the single pipe connection operation, fundamentally eliminating the human accidents caused by the easy omission of the traditional hidden structure into the well. In addition, the conical pipe body with double arrays of circular filter holes and strip-shaped filter holes can flexibly adjust the aperture size and wall thickness parameters according to the cleanliness and sand content of the drilling fluid, and the modular design allows individual replacement of damaged parts, combining the comprehensive advantages of filtering efficiency, service life and maintenance economy.

[0039] In one embodiment, as shown in Figure 1 , Figure 3 , and Figure 4 , the first filter hole array is composed of 40 layers along the first filter hole unit, and each layer of the first filter hole unit includes 12 uniformly distributed circular filter holes 24. The second filter hole array is composed of 4 layers along the second filter hole unit, and each layer of the second filter hole unit includes 6 uniformly distributed strip-shaped filter holes 25.

[0040] Understandably, the circular filter holes 24 are symmetrically arranged about the central axis of the conical pipe body, and the strip-shaped filter holes 25 are also symmetrically arranged about the central axis of the conical pipe body, so that the jets generated by the drilling fluid flowing in the inner flow filter pipe cancel each other out, and the erosion of the drilling fluid on the filter itself can be reduced. Specifically, by symmetrically arranging the first filter hole unit (each layer has a circular filter hole 24) and the second filter hole unit (each layer has a strip-shaped filter hole 25) on the central axis of the conical pipe body 21, a completely balanced inflow channel in the circumferential direction is constructed. When the drilling fluid enters the inner flow filter pipe 2 (conical pipe body 21) from all directions at the same time, not only can it filter out impurities and larger solid particles to leave outside the conical pipe body 21, but also the momentum vectors of the high-speed jets cancel each other out, eliminating the local erosion of the inner wall of the inner flow filter pipe 2 and protecting the structural integrity of the liquid filter structure itself, and the filtered drilling fluid will not jet impact the inner wall of the drill pipe, thereby preventing the drill pipe from being eroded and improving the service life of the oil drill pipe. This dual-array parameterization configuration not only ensures the flow area, but also optimizes the filtering efficiency and self-erosion resistance through the differential design of the number of layers and holes (dense circular holes for main filtering and sparse strip-shaped holes for anti-clogging).

[0041] Further, it can be understood that the filtering direction of the traditional filter (funnel-shaped) is from inside to outside: the drilling fluid first enters the internal cavity of the filter, and then is jetted out from the wall filter holes to form high-speed jets directly impacting the inner wall of the drill pipe.

[0042] The filtering direction of the liquid filter structure of the present application is from outside to inside: through the integrated structure of the conical pipe body 21 and the flow guide base 1 (flow guide sealing part 13), an inflow space is formed between the outer wall of the conical pipe body 21 and the inner wall of the drill pipe, and the drilling fluid flows into the inner cavity of the inner flow filter pipe 2 through the filter holes (circular filter holes 24 and strip-shaped filter holes 25) under the action of pressure, impurities are blocked outside the conical pipe body 21, and the filtered liquid is forced to converge in the inner cavity of the flow guide sealing part 13 and flows out from the overflow hole 14 at the bottom thereof in parallel to the inner wall of the drill pipe, completely avoiding the vertical / oblique impact of the jets on the inner wall of the drill pipe. The symmetric arrangement of the circular filter holes 24 and the strip-shaped filter holes 25 in the circumferential direction of the pipe wall ensures that the inflow is balanced in all directions, and the internal jet momentum cancels each other out.

[0043] In one embodiment, as shown in Figure 1 , Figure 3 , and Figure 4As shown, the diameter of the circular filter hole 24 is 6 mm, and the center distance between adjacent circular filter holes 24 in each layer of the first filter hole unit is 12 mm. The length of the strip-shaped filter hole 25 is 20 mm, and the width is 6 mm, and the center distance between adjacent strip-shaped filter holes 25 in each layer of the second filter hole unit is 25 mm. Understandably, in the circumferential direction of the conical pipe body 21, the circular filter holes 24 and the strip-shaped filter holes 25 in each layer are uniformly distributed at equal intervals, ensuring that the 360° annular pressure field is uniformly transmitted to each inflow point, avoiding the partial high-pressure area caused by the flow deviation and erosion concentration. In the axial direction, the dense circular filter holes 24 (layer spacing 12 mm) and the sparse strip-shaped filter holes 25 (layer spacing 25 mm) form a gradient filter flow channel. When the drilling fluid enters the filter hole from the inflow space under the action of pressure, the velocity vector size of the jet flow in each direction is equal, the direction is symmetrical, and the momentum is offset, thereby converting the disordered turbulent jet flow of the traditional filter into an orderly laminar flow. When the drilling fluid flows out of the filter hole (circular filter hole 24 and strip-shaped filter hole 25) under the action of pressure, the size of the filter hole determines the flow resistance of the drilling fluid. Smaller diameter filter holes will produce greater flow resistance, and higher pressure is required to make the drilling fluid pass through; while larger diameter filter holes have smaller flow resistance, and the drilling fluid can pass through smoothly under lower pressure. By reasonably designing the diameter and size of the two kinds of holes, the pressure distribution of the drilling fluid in the inflow space can be controlled, so that the drilling fluid can pass through the filter hole with appropriate pressure and flow rate.

[0044] In an embodiment, as shown in Figure 1 and Figure 5 The flow guide base 1 includes a hanging clamping part 11, a flow guide sealing part 13, and a first chamfer 12 connected between the hanging clamping part 11 and the flow guide sealing part 13; the hanging clamping part 11 is threadedly connected with the butt joint screw base 23, and the flow guide sealing part 13 is clearance-fitted with the mounting clamping groove base 41 of the first drill pipe 4; a plurality of overflow holes 14 for the flow of drilling fluid out of the conical pipe body 21 are arranged on the flow guide sealing part 13.

[0045] Understandably, the diameter of the hanging clamping part 11 is greater than the diameter of the flow guide sealing part 13, the flow guide sealing part of the flow guide base is provided with overflow holes, which has the function of guiding the flow of drilling fluid, so that the flow of drilling fluid is parallel to the pipe wall of the drill pipe to reduce the erosion effect, and the inner flow filter pipe can be kept centered in the drill pipe, and the clearance is uniform to ensure good filtering effect. The flow guide base can also simultaneously avoid the inner flow filter pipe installed on the upper part thereof from falling into the well due to damage and failure.

[0046] In an embodiment, as shown in Figure 1 and Figure 5As shown, the flow guide sealing part 13 is provided with 19 flow holes 14 with a diameter of 10 mm, which are arranged in three concentric circular arrays, and the number of flow holes 14 in each circle from inside to outside is 1, 6 and 12, respectively, and the radial spacing between adjacent circles is 4 mm. Understandably, the three concentric circular distribution of flow holes 14 increases the number of holes from 1 to 6 to 12, which gradually distributes the filtered liquid from the center to the edge, ensuring uniform and smooth outflow, and avoiding single-hole high-speed jet impact on the inner wall of the drill pipe; the 4mm inter-circle spacing ensures the structural strength of the hole wall thickness, prevents the base from being insufficient due to too many holes, and realizes the balance of outflow and structural safety.

[0047] In an embodiment, as shown in Figure 1 、 Figure 3 and Figure 7 , the anti-slip handle 3 includes a holding part 31 and an anti-slip step 32 connected at both ends of the holding part 31, and a threaded connection part 321 is arranged on the anti-slip step 32 close to the inner flow filter pipe 2, which is screwed with the connecting stud 22. Understandably, the anti-slip handle 3 is designed with a variable diameter of the holding part 31 and the anti-slip steps 32 at both ends, which provides anti-slip and stop for the operator when grabbing, and the handle structure exposed to the threaded joint inside the second drill pipe 5 realizes the visual anti-missing function, that is, the wellhead personnel can directly observe the position of the anti-slip handle 3 during the single pipe connection operation, and the drill pipe can be connected only after the filter is taken out by holding the holding part 31, which fundamentally eliminates the risk of forgetting to take out the traditional concealed structure due to observation. The cooperation of the threaded connection part 321 and the connecting stud 22 (inner flow filter pipe 2) ensures the integrated operation convenience of the entire filter assembly.

[0048] In an embodiment, as shown in Figure 1 、 Figure 3 and Figure 7 , a second chamfer 33 is arranged between the anti-slip step 32 and the holding part 31. Understandably, the second chamfer 33 can eliminate the sharp edge burrs generated by machining at the variable diameter transition of the anti-slip step 32 and the holding part 31, prevent the operator from scratching his hand when grabbing, and at the same time, disperse the stress concentration at this part, improve the fatigue life and operation safety of the handle.

[0049] The present invention also provides a liquid filter, including the above-mentioned anti-erosion and anti-detachment drilling fluid filter structure for oil drill pipe. In the liquid filter of the above embodiment of the present invention, the anti-erosion and anti-detachment drilling fluid filter structure for oil drill pipe includes a flow guide base 1, an internal flow filter pipe 2 and an anti-slip handle 3 that are sequentially threaded and coaxially arranged; the flow guide base 1 is engaged with the mounting slot 41 of the first drill pipe 4, and the connecting coupling head 42 of the first drill pipe 4 is threadedly connected to the flow guide cone 51 of the second drill pipe 5. The internal flow filter pipe 2 and the anti-slip handle 3 are both installed in the flow guide cavity 52 of the second drill rod 5. The internal flow filter pipe 2 includes a tapered pipe body 21, a connecting stud 22 disposed on the tapered pipe body 21 and threadedly connected to the anti-slip handle 3, and a mating screw seat 23 disposed on the tapered pipe body 21 and threadedly connected to the flow guide base 1. A first filter hole array and a second filter hole array are alternately distributed along the circumferential direction of the pipe wall of the tapered pipe body 21. The first filter hole array is composed of multiple layers of first filter hole units distributed along the circumferential direction of the pipe wall of the tapered pipe body 21, and each layer of the first filter hole unit includes multiple evenly distributed circular filter holes 24. The second filter hole array is composed of multiple layers of second filter hole units distributed along the circumferential direction of the pipe wall of the tapered pipe body 21, and each layer of the second filter hole unit includes multiple evenly distributed strip-shaped filter holes 25.

[0050] The working process of the liquid filter in the above embodiments of the present invention is roughly as follows:

[0051] The guide base 1, the internal flow filter pipe 2, and the anti-slip handle 3 are sequentially threaded together to form the liquid filter assembly. By holding the anti-slip handle 3, it is placed in the guide cavity (52) of the second drill pipe 5, so that the suspension locking part 11 of the guide base 1 is locked and positioned with the mounting slot seat 41 of the first drill pipe 4. During drilling operations, the drilling pump is started, and the drilling fluid flows from the inlet space between the outer wall of the tapered tube body 21 and the inner wall of the drill pipe under pressure, and flows from the outside to the inside through the circumferentially distributed circular filter holes 24 and strip filter holes 25. Inside the filter tube 2, debris and solid particles are blocked outside the filter tube. After the filtered liquid gathers in the inner cavity of the flow-guiding sealing part 13, it flows out axially parallel to the inner wall of the drill pipe through 19 flow holes 14 arranged in a three-circle concentric array at the bottom. Since the anti-slip handle 3 is exposed on the internal threaded joint of the drill pipe, the wellhead personnel must actively remove the filter through the grip part 31 before connecting a single drill pipe, so as to make the threaded connection between the first drill pipe 4 and the second drill pipe 5, thereby eliminating the risk of the liquid filter being left in the well. Repeating the above process can achieve continuous construction.

[0052] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An anti-erosion and anti-falling drilling fluid filter structure for an oil drilling rod, characterized in that, It comprises a flow guide base (1), an inner flow filter pipe (2) and an anti-skid handle (3) which are connected in sequence and coaxially arranged; the flow guide base (1) is clamped with the mounting clamping groove seat (41) of the first drill rod (4), the connecting coupling head (42) of the first drill rod (4) is threadedly connected with the flow guide cone part (51) of the second drill rod (5); The inner flow filter pipe (2) and the anti-skid handle (3) are arranged in the flow guide cavity (52) of the second drill rod (5), the inner flow filter pipe (2) comprises a conical pipe body (21), a connecting stud (22) arranged on the conical pipe body (21) and threadedly connected with the anti-skid handle (3), and a butt joint screw seat (23) arranged on the conical pipe body (21) and threadedly connected with the flow guide base (1); a first filter hole array and a second filter hole array are arranged in the circumferential direction of the pipe wall of the conical pipe body (21); wherein the first filter hole array is composed of a plurality of layers of first filter hole units arranged in the circumferential direction of the pipe wall of the conical pipe body (21), each layer of the first filter hole unit comprises a plurality of uniformly distributed circular filter holes (24); The second filter hole array is composed of a plurality of layers of second filter hole units arranged in the circumferential direction of the pipe wall of the conical pipe body (21), each layer of the second filter hole unit comprises a plurality of uniformly distributed strip-shaped filter holes (25).

2. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 1, characterized in that, The first filter hole array is composed of 40 layers of the first filter hole units, each layer of the first filter hole unit comprises 12 uniformly distributed circular filter holes (24); The second filter hole array is composed of 4 layers of the second filter hole units, each layer of the second filter hole unit comprises 6 uniformly distributed strip-shaped filter holes (25).

3. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 2, characterized in that, The diameter of the circular filter hole (24) is 6mm, and the center distance between adjacent circular filter holes (24) in each layer of the first filter hole unit is 12mm; The length of the strip-shaped filter hole (25) is 20mm, the width is 6mm, and the center distance between adjacent strip-shaped filter holes (25) in each layer of the second filter hole unit is 25mm.

4. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 3, characterized in that, The flow guide base (1) comprises a hanging clamping part (11), a flow guide sealing part (13), and a first chamfer (12) connected between the hanging clamping part (11) and the flow guide sealing part (13); the hanging clamping part (11) is threadedly connected with the butt joint screw seat (23), the flow guide sealing part (13) is clearance-fitted with the mounting clamping groove seat (41) of the first drill rod (4); a plurality of overflow holes (14) for the flow of drilling fluid out of the conical pipe body (21) are arranged on the flow guide sealing part (13).

5. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 4, characterized in that, 19 overflow holes (14) with a diameter of 10mm are arranged on the flow guide sealing part (13), the overflow holes (14) are arranged in three concentric circular arrays, the number of the overflow holes (14) in each circle from inside to outside is 1, 6 and 12 respectively, and the radial distance between adjacent circles is 4mm.

6. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 5, characterized in that, The anti-skid handle (3) comprises a holding part (31) and anti-skid steps (32) connected at both ends of the holding part (31), and a threaded connecting part (321) is arranged on the anti-skid step (32) close to the inner flow filter pipe (2), and the threaded connecting part (321) is threadedly connected with the connecting stud (22).

7. The anti-erosion and anti-falling drilling fluid filter structure for oil drilling rods according to claim 6, characterized in that, A second chamfer (33) is arranged between the anti-skid step (32) and the holding part (31).

8. A liquid filter, characterized by The anti-erosion and anti-falling drilling fluid filtering structure for the petroleum drill pipe comprises the anti-erosion and anti-falling drilling fluid filtering structure as claimed in any one of claims 1-7.

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